/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alipay.sofa.registry.remoting;

import java.util.concurrent.Executor;

/**
 *
 * @author shangyu.wh
 * @version $Id: ChannelHandler.java, v 0.1 2017-11-20 20:45 shangyu.wh Exp $
 */
public interface ChannelHandler<T> {

    /**
     * The enum Handler type.
     */
    enum HandlerType {
        LISENTER,
        PROCESSER
    }

    /**
     * The enum Invoke type.
     */
    enum InvokeType {
        SYNC,
        ASYNC
    }

    /**
     * on channel connected.
     *
     * @param channel
     * @throws RemotingException
     */
    void connected(Channel channel) throws RemotingException;

    /**
     * on channel disconnected.
     *
     * @param channel channel.
     * @throws RemotingException
     */
    void disconnected(Channel channel) throws RemotingException;

    /**
     * on message received.
     *
     * @param channel channel.
     * @param message message.
     * @throws RemotingException
     */
    void received(Channel channel, T message) throws RemotingException;

    /**
     * on message reply.
     *
     * @param channel
     * @param message
     * @return
     * @throws RemotingException
     */
    Object reply(Channel channel, T message) throws RemotingException;

    /**
     * on exception caught.
     * @param channel channel.
     * @param message message.
     * @param exception exception.
     * @throws RemotingException
     */
    void caught(Channel channel, T message, Throwable exception) throws RemotingException;

    /**
     * check handlerType
     *
     * @return
     */
    HandlerType getType();

    /**
     * return processor request class name
     *
     * @return
     */
    Class interest();

    /**
     * Select Sync process by reply or Async process by received
     * @return
     */
    default InvokeType getInvokeType() {
        return InvokeType.SYNC;
    }

    /**
     * specify executor for processor handler
     * @return
     */
    default Executor getExecutor() {
        return null;
    }
}